This invention relates to index tabs, and more particularly to self adhesive index tabs that can be attached by the user to the edge of sheets.
Many index tab constructions have been proposed heretofore, and some of the prior patents in this field include the following: U.S. Pat. No. 3,314,529; U.S. Pat. No. 3,473,827; U.S. Pat. No. 4,972,615; U.S. Pat. No. 5,662,976; U.S. Pat. No. 6,086,107; U.S. Pat. No. 6,013,154; U.S. Pat. No. 6,132,831; Great Britain Patent No. 2,006,683A; and Great Britain Patent No. 1,212,619.
However, the tabs and tab sheets which have been proposed heretofore are subject to various problems. For example, when a polyester sheet is laminated to a paper liner, and is stored for a time prior to printing in a laser or ink jet printer, certain problems may arise. If the tabs on the polyester sheet have a free edge, they may fold outward and interfere with smooth rapid feeding of the sheets through the printer; and paper jams may occur. In addition, under high humidity conditions curling of the sheets may occur. Further, if the matrix of polyester around the tabs is removed, release material on the liner may engage the printer rollers and may cause feeding problems.
In addition, with prior art tabs, it is often difficult to locate the tabs accurately on the edge of the sheet material to which the tab is to be fastened.
In accordance with one illustrative embodiment of the invention, sheets of index tabs may include a liner sheet and an overlying plastic sheet, preferably of translucent polyester, with the index tabs being die cut through the plastic sheet. The liner sheet has a release surface, and a layer of pressure sensitive adhesive is located between the two sheets, except for certain non-adhesive strip areas. The sheets may be letter size, 8xc2xdxc3x9711 inches, or A-4 paper size, or have other dimensions.
The index tabs have three areas, including first and second printable areas of approximately equal size, and a securing area extending from one of the printable areas. A score line is provided between the two printable areas to facilitate folding them over against each other, with two full thickness ties at the ends of the score line. A narrow strip area free of adhesive is located on the securing area next to the adjacent printable area.
After the sheets are printed, preferably with the die cut tabs and the entire plastic sheet intact, a printed tab may be removed, and the two adhesive coated printable areas are folded together. This forms a lip or step immediately adjacent the adhesive free strip area. The index tab is then attached to the edge of sheet material, with the lip or step being placed against the edge of the sheet material, and with any needed slight adjustments being facilitated by the adhesive free area; and then the adhesive coated securing area is pressed onto the sheet to accurately secure the tab in position.
Concerning other aspects or features of the invention, the tabs are preferably formed of translucent plastic material such as polyester.
When the sheets are being printed, with indexing information, the full plastic sheet including the matrix around the die cut tabs is fed through the printer. Cuts may be provided in the plastic sheet from the edges of the plastic sheets to the die cut tabs and between the die cut tabs, to avoid curling of the two layer sheet assemblies, which might otherwise occur as a result of non-uniform moisture absorption.
The plastic sheet material is preferably treated to receive a coating, normally a colored coating such as colored ink, to form a suitable background for printing indexing information on the tabs, using a laser ink jet printer or by any known printing method. The colored coating is preferable on the side of the plastic sheet to which the adhesive is applied, facing the liner, but may be on the outer surface of the plastic sheets.
It is to be understood that the tabs per se could be sold individually rather than on letter size sheets, or in strip format, for examples.
Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and from the accompanying drawings.